Hi barrelhouse,

Great gravy, how many Volvo automobiles do you own?

Nice to see you back. It's been six years since your last brickboard.com post.

The warm-up regulator you mention was a part of a different Bosch injection system on the Saab, the mighty K-Jetronic, I believe. Am not sure.

You write:
"The local mechanic that services imports and is well versed in Bosch fuel injection has become flummoxed.

"He has assessed that there is no fuel pressure on start up but says that he has no documentation for this car nor the proper fittings to measure fuel pressure."

How can he tell whether the fuel lines have fuel pressure? Did he crack a low-pressure return line fitting? Did he listen for some fuel pump action.

Did your mechanic do any research on the problem? You have www.brickboard.com and innumerable free resources.

A well versed mechanic trained or experienced on a Bosch, AC Delco, whatever Ford uses, Toyota, and what have you, Engine Control System (not merely fuel injection!) should know their way around the OBD-1 ECUs of your 1993 Volvo 940 Turbo. Your Bosch Engine Control or Management System comes in two parts. One for fuel Bosch LH Jetronic and the other as the ignition the Bosch EZK.

So, you have the 700-900-90 FAQ hosted right here on your www.brickboard.com.

https://www.brickboard.com/FAQ/700-900/

As a 700-900-90 Volvo owner, I urge you to study the 700-900-90 FAQ throughly. Do you have a Haynes or Volvo green factory service (search online) repair manuals?

What you mention may happen on a cold or, more often, a hot start (hot soak?). Meaning the engine has been recently run and is hot, and the engine does not start when hot. So, for hot start problems, see:

https://www.brickboard.com/FAQ/700-900/HotStartProblemQuickReferenceGuide.htm


Run the feeble and overcompensating OBD. It is a guide to diagnosis. Many ignore it. Many more malign it. I always use and check it frequently. It's free to do so. Why not? Sockets two for fuel injection and socket six for ignition (and EGR, if fitted).

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

An entry on starting and charging.

https://www.brickboard.com/FAQ/700-900/ElectricalStarting.htm

Fuel injection relay. Oft and aforementioned. Cracks in solder welds under the white plastic cover, corrosion at the relay junction box under the dash behind the ashtray of your 940. (That relay junction box is a source of corrosion at the terminals. Sometimes you'll see warped plastic from the heat produced by current passing through corroded junctions or connectors.

How the ignition power stage, and the connector? Some new thermal paste, like that use between processors and their heat sinks, between the ignition amplifier and the metal heat sink.

Connection to or a faulty the Engine Coolant Temperature sensor. OBD check may show this.

Faulty EGR, if fitted. Though this begins as drive ability problems as the EGR valve usually sticks open.

If indeed a fuel problem, you can check the fuel pump action at the fuel injection relay and listen for the pumps.

How old is the timing belt? Or has it been sometime since you reset the timing belt tension? If not, or, if a new timing belt has not had the tension reset at any time, the timing belt can move a tooth.

When looking at the air intake system, from the air filer up to the intake valves, and all hoses, seals, gaskets ... the PCV is okay? The pipes are sealed. No air intake leaks?

Else, I dunno. Hope that helps.

Read the FAQ.

Thanks,

Dud.